/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2013 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Class
    Foam::fieldValues::faceSource

Group
    grpFieldFunctionObjects

Description
    This function object provides a 'face source' variant of the fieldValues
    function object.  Given a list of user-specified fields and a selection
    of mesh (or general surface) faces, a number of operations can be
    performed, such as sums, averages and integrations.

    \linebreak
    For example, to calculate the volumetric or mass flux across a patch,
    apply the 'sum' operator to the flux field (typically \c phi)

    Example of function object specification:
    \verbatim
    faceSource1
    {
        type            faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        ...
        log             yes;
        valueOutput     true;
        surfaceFormat   none;
        source          faceZone;
        sourceName      f0;
        operation       sum;
        weightField     alpha1;
        fields
        (
            p
            phi
            U
        );
    }
    \endverbatim

    \heading Function object usage
    \table
        Property     | Description             | Required    | Default value
        type         | type name: faceSource   | yes         |
        log          | write data to standard output | no    | no
        valueOutput  | write the output values | yes         |
        surfaceFormat | output value format    | no          |
        source       | face source: see below  | yes         |
        sourceName   | name of face source if required  | no |
        operation    | operation to perform    | yes         |
        weightField  | name of field to apply weighting | no |
        scaleFactor  | scale factor            | no          | 1
        fields       | list of fields to operate on | yes    |
    \endtable

    \linebreak
    Where \c source is defined by
    \plaintable
        faceZone     | requires a 'sourceName' entry to specify the faceZone
        patch        | requires a 'sourceName' entry to specify the patch
        sampledSurface | requires a 'sampledSurfaceDict' sub-dictionary
    \endplaintable

    \linebreak
    The \c operation is one of:
    \plaintable
       none          | no operation
       sum           | sum
       sumMag        | sum of component magnitudes
       sumDirection  | sum values which are positive in given direction
       sumDirectionBalance | sum of balance of values in given direction
       average       | ensemble average
       weightedAverage | weighted average
       areaAverage   | area weighted average
       areaIntegrate | area integral
       min           | minimum
       max           | maximum
       CoV           | coefficient of variation: standard deviation/mean
       areaNormalAverage| area weighted average in face normal direction
       areaNormalIntegrate | area weighted integral in face normal directon
    \endplaintable

Note
    - The values reported by the areaNormalAverage and areaNormalIntegrate
      operations are written as the first component of a field with the same
      rank as the input field.
    - faces on empty patches get ignored
    - if the field is a volField the \c faceZone can only consist of boundary
      faces
    - all fields are oriented according to the \c faceZone (so you might
      e.g. see negative pressure)
    - using \c sampledSurfaces:
        - not available for surface fields
        - if interpolate=true they use \c interpolationCellPoint
          otherwise they use cell values
        - each triangle in \c sampledSurface is logically only in one cell
          so interpolation will be wrong when triangles are larger than
          cells.  This can only happen for sampling on a \c triSurfaceMesh
        - take care when using isoSurfaces - these might have duplicate
          triangles and so integration might be wrong

SeeAlso
    Foam::fieldValues
    Foam::functionObject
    Foam::OutputFilterFunctionObject

SourceFiles
    faceSource.C

\*---------------------------------------------------------------------------*/

#ifndef faceSource_H
#define faceSource_H

#include "NamedEnum.H"
#include "fieldValue.H"
#include "surfaceFieldsFwd.H"
#include "volFieldsFwd.H"
#include "surfaceWriter.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

class sampledSurface;

namespace fieldValues
{

/*---------------------------------------------------------------------------*\
                         Class faceSource Declaration
\*---------------------------------------------------------------------------*/

class faceSource
:
    public fieldValue
{

public:

    // Public data types

        //- Source type enumeration
        enum sourceType
        {
            stFaceZone,
            stPatch,
            stSampledSurface
        };

        //- Source type names
        static const NamedEnum<sourceType, 3> sourceTypeNames_;


        //- Operation type enumeration
        enum operationType
        {
            opNone,
            opSum,
            opSumMag,
            opSumDirection,
            opSumDirectionBalance,
            opAverage,
            opWeightedAverage,
            opAreaAverage,
            opAreaIntegrate,
            opMin,
            opMax,
            opCoV,
            opAreaNormalAverage,
            opAreaNormalIntegrate
        };

        //- Operation type names
        static const NamedEnum<operationType, 14> operationTypeNames_;


private:

    // Private Member Functions

        //- Set faces to evaluate based on a face zone
        void setFaceZoneFaces();

        //- Set faces to evaluate based on a patch
        void setPatchFaces();

        //- Set faces according to sampledSurface
        void sampledSurfaceFaces(const dictionary&);

        //- Combine mesh faces and points from multiple processors 
        void combineMeshGeometry
        (
            faceList& faces,
            pointField& points
        ) const;

        //- Combine surface faces and points from multiple processors 
        void combineSurfaceGeometry
        (
            faceList& faces,
            pointField& points
        ) const;


protected:

    // Protected data

        //- Surface writer
        autoPtr<surfaceWriter> surfaceWriterPtr_;

        //- Source type
        sourceType source_;

        //- Operation to apply to values
        operationType operation_;

        //- Weight field name - optional
        word weightFieldName_;

        //- Scale factor
        scalar scaleFactor_;

        //- Global number of faces
        label nFaces_;


        // If operating on mesh faces (faceZone, patch)

            //- Local list of face IDs
            labelList faceId_;

            //- Local list of patch ID per face
            labelList facePatchId_;

            //- List of +1/-1 representing face flip map
            //  (1 use as is, -1 negate)
            labelList faceSign_;


        // If operating on sampledSurface

            //- underlying sampledSurface
            autoPtr<sampledSurface> surfacePtr_;


    // Protected Member Functions

        //- Initialise, e.g. face addressing
        void initialise(const dictionary& dict);

        //- Return true if the field name is valid
        template<class Type>
        bool validField(const word& fieldName) const;

        //- Return field values by looking up field name
        template<class Type>
        tmp<Field<Type> > getFieldValues
        (
            const word& fieldName,
            const bool mustGet = false
        ) const;

        //- Apply the 'operation' to the values. Operation has to
        //  preserve Type.
        template<class Type>
        Type processSameTypeValues
        (
            const Field<Type>& values,
            const vectorField& Sf,
            const scalarField& weightField
        ) const;

        //- Apply the 'operation' to the values. Wrapper around
        //  processSameTypeValues. See also template specialisation below.
        template<class Type>
        Type processValues
        (
            const Field<Type>& values,
            const vectorField& Sf,
            const scalarField& weightField
        ) const;

        //- Output file header information
        virtual void writeFileHeader(const label i);


public:

    //- Run-time type information
    TypeName("faceSource");


    //- Construct from components
    faceSource
    (
        const word& name,
        const objectRegistry& obr,
        const dictionary& dict,
        const bool loadFromFiles = false
    );


    //- Destructor
    virtual ~faceSource();


    // Public Member Functions

        // Access

            //- Return the source type
            inline const sourceType& source() const;

            //- Return the local list of face IDs
            inline const labelList& faceId() const;

            //- Return the local list of patch ID per face
            inline const labelList& facePatch() const;

            //- Return the list of +1/-1 representing face flip map
            inline const labelList& faceSign() const;


        // Function object functions

            //- Read from dictionary
            virtual void read(const dictionary&);

            //- Calculate and write
            virtual void write();

            //- Templated helper function to output field values
            template<class Type>
            bool writeValues(const word& fieldName);

            //- Filter a surface field according to faceIds
            template<class Type>
            tmp<Field<Type> > filterField
            (
                const GeometricField<Type, fvsPatchField, surfaceMesh>& field,
                const bool applyOrientation
            ) const;

            //- Filter a volume field according to faceIds
            template<class Type>
            tmp<Field<Type> > filterField
            (
                const GeometricField<Type, fvPatchField, volMesh>& field,
                const bool applyOrientation
            ) const;
};


//- Specialisation of processing scalars
template<>
scalar faceSource::processValues
(
    const Field<scalar>& values,
    const vectorField& Sf,
    const scalarField& weightField
) const;


//- Specialisation of processing vectors
template<>
vector faceSource::processValues
(
    const Field<vector>& values,
    const vectorField& Sf,
    const scalarField& weightField
) const;


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace fieldValues
} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include "faceSourceI.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#ifdef NoRepository
    #include "faceSourceTemplates.C"
#endif

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //
